Research ArticleEnergy Efficient Hybrid Dual Axis Solar Tracking System
Rashid Ahammed Ferdaus1 Mahir Asif Mohammed1 Sanzidur Rahman1
Sayedus Salehin2 and Mohammad Abdul Mannan1
1 Faculty of Engineering American International University-Bangladesh Road 14 Kemal Ataturk Avenue BananiDhaka 1213 Bangladesh
2Department of Mechanical and Chemical Engineering Islamic University of Technology (IUT)Organisation of Islamic Cooperation (OIC) Board Bazar Gazipur 1704 Bangladesh
Correspondence should be addressed to Rashid Ahammed Ferdaus rashidferdausyahoocom
Received 16 April 2014 Accepted 16 June 2014 Published 8 July 2014
Academic Editor Jayanta Deb Mondol
Copyright copy 2014 Rashid Ahammed Ferdaus et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited
This paper describes the design and implementation of an energy efficient solar tracking system from a normal mechanicalsingle axis to a hybrid dual axis For optimizing the solar tracking mechanism electromechanical systems were evolved throughimplementation of different evolutional algorithms and methodologies To present the tracker a hybrid dual-axis solar trackingsystem is designed built and tested based on both the solar map and light sensor based continuous tracking mechanism Theselight sensors also compare the darkness and cloudy and sunny conditions assisting daily tracking The designed tracker can tracksunrsquos apparent position at different months and seasons thereby the electrical controlling device requires a real time clock devicefor guiding the tracking system in seeking solar position for the seasonal motion So the combination of both of these trackingmechanisms made the designed tracker a hybrid one The power gain and system power consumption are compared with a staticand continuous dual axis solar tracking system It is found that power gain of hybrid dual axis solar tracking system is almostequal to continuous dual axis solar tracking system whereas the power saved in system operation by the hybrid tracker is 4444compared to the continuous tracking system
1 Introduction
During the last few years the renewable energy sourceslike solar energy have gained much importance in all overthe world Different types of renewable or green energyresources like hydropower wind power and biomass energyare currently being utilized for the supply of energy demandAmong the conventional renewable energy sources solarenergy is the most essential and prerequisite resource ofsustainable energy [1 2]
Solar energy refers to the conversion of the sunrsquos rays intouseful forms of energy such as electricity or heat A photovol-taic cell commonly called a solar cell or PV is the technologyused to convert solar energy directly into electrical powerThe physics of the PV cell (solar cell) is very similar to theclassical p-n junction diode Sunlight is composed of photonsor particles of solar energy Semiconductor materials withinthe PV cell absorb sunlight which knocks electrons from their
atoms allowing electrons to flow through the material toproduce electricity [3 4] Because of its cleanliness ubiquityabundance and sustainability solar energy has become wellrecognized and widely utilized [5]
Different researches estimate that covering 016 of theland on earth with 10 efficient solar conversion systemswould provide 20 TW of power nearly twice the worldrsquos con-sumption rate of fossil energy [6]This proves the potential ofsolar energywhich in turn points out the necessity of trackingmechanism in solar systems The tracking mechanism isan electromechanical system that ensures solar radiation isalways perpendicular to the surface of the photovoltaic cells(solar cells) which maximizes energy harnessing [7]
Over the years researchers have developed smart solartrackers for maximizing the amount of energy generationBefore the introduction of solar trackingmethods static solarpanels were positioned with a reasonable tilted angle basedon the latitude of the location In this competitive world of
Hindawi Publishing CorporationJournal of Renewable EnergyVolume 2014 Article ID 629717 12 pageshttpdxdoiorg1011552014629717
2 Journal of Renewable Energy
Sun
West
NorthEarthrsquos surface
South
East
120573
120572
Figure 1 Illustration of the solar angles (a) altitude angle 120572 (b)azimuthal angle 120573 The solar path corresponds to a day in the earlyfall or late winter seasons in the northern hemisphere that is justprior to the spring equinox or just after the fall equinox Solar noonis the time of day when 120573 = 180 degree that is the sun is directly atsouth and is halfway between sunrise and sunset
advanced scientific discoveries the introductions of auto-mated systems improve existing power generation by 50 [8]
There are mainly two types of solar trackers on the basisof their movement degrees of freedoms These are single axissolar tracker and dual axis solar tracker Again these twosystems are further classified on the basis of their trackingtechnologies Active passive and chronological trackers arethree of them [9 10]
Previous researchers used single axis tracking systemwhich follows only the sunrsquos daily motion [11] But the earthfollows a complex motion that consists of the daily motionand the annual motion The daily motion causes the sun toappear in the east to west direction over the earth whereasthe annual motion causes the sun to tilt at a particular anglewhile moving along east to west direction [12]
Figure 1 shows the daily and annual motion of the sunThe sunrsquos location in the sky relative to a location on thesurface of the earth can be specified by two angles as shownin Figure 1They are (1) the solar altitude angle (120572) and (2) thesolar azimuth angle (120573) Angle120572 is the angle between the sunrsquosposition and the horizontal plane of the earthrsquos surface whileangle120573 specifies the angle between a vertical plane containingthe solar disk and a line running due south [13]
Solar tracking is best achieved when the tilt angle ofthe solar tracking systems is synchronized with the seasonalchanges of the sunrsquos altitude An ideal tracker would allowthe solar modules to point towards the sun compensatingfor both changes in the altitude angle of the sun (throughoutthe day) and latitudinal offset of the sun (during seasonalchanges) So the maximum efficiency of the solar panel is notbeing used by single axis tracking systemwhereas double axistracking would ensure a cosine effectiveness of one
In active tracking or continuous tracking the position ofthe sun in the sky during the day is continuously determinedby sensors The sensors will trigger the motor or actuatorto move the mounting system so that the solar panels willalways face the sun throughout the day If the sunlight is notperpendicular to the tracker then there will be a differencein light intensity on one light sensor compared to anotherThis difference can be used to determine in which direction
the tracker has to be tilted in order to be perpendicularto the sun This method of sun tracking is reasonablyaccurate except on very cloudy days when it is hard forthe sensors to determine the position of the sun in the sky[14]
Passive tracker unlike an active tracker which determinesthe position of the sun in the sky moves in response to animbalance in pressure between two points at both ends ofthe tracker The imbalance is caused by solar heat creatinggas pressure on a ldquolow boiling point compressed gas fluidthat is driven to one side or the otherrdquo which then movesthe structure However this method of sun tracking is notaccurate [15 16]
A chronological tracker is a time-based tracking systemwhere the structure is moved at a fixed rate throughout theday as well for different months Thus the motor or actuatoris controlled to rotate at a slow average rate of one revolutionper day (15∘ per hour) This method of sun tracking is moreenergy efficient [17]
To track the sunrsquos movement accurately dual axis trackingsystem is necessary The activecontinuous tracking systemtracks the sun for light intensity variation with precisionHence the power gain from this system is very high [18]But to achieve this power gain the system uses two differentmotors continuously for two different axes As a result italways consumes a certain amount of extra power comparedto time-based tracking system Therefore to reduce thispower loss a combination of active and time-based trackingcould be the suitable alternative to this system Finally themotivation of the research was to design and implement ahybrid dual axis solar tracking system which reduces themotor power consumption while tracking accurately
A simple energy efficient and rugged tracking modelis presented in this paper in order to build a hybrid dualaxis solar tracker To track the sunrsquos daily motion thatis from east to west direction a pair of light sensors areused and to track the seasonal motion of the sun real timeclock (RTC) is used to create the accurate azimuth anglefrom some predetermined parameters The light intensity iscompared by microcontroller and it generates the suitablecontrol signals to move the motors in proper direction Soa driver circuit is used to increase the voltage and currentlevel for the operation of the motors Two full geared steppermotors are used for rotating the solar module in two differentaxes
A versatile mechanical system is introduced as a linearactuator to create proper tilt angle In addition this linearactuator has high weight lifting capability which is observedexperimentally It is found that energy efficient hybrid dualaxis tracking yields almost same energy as continuous dualaxis solar tracking system It is also observed that in hybridtracking system one motor can remain idle for one monthand thus reduces more than 44 of power consumption ascompared with continuous dual axis solar tracking systemThismechanismproved significant benefit of reducing energyconsumption by hybrid tracker sacrificing a very little track-ing loss This paper also represents the comparative studybetween the continuousactive and hybrid solar trackingsystem
Journal of Renewable Energy 3
(a) (b)
Figure 2 Design and implementation of linear actuator (a) implementation and placement of linear actuator with the aluminium body ofpanel carrier (b) hardware design of linear actuator in computer aided drafting tool
2 Design and Implementation Process
The whole work involves the reading of different sensorvalues and then comparing them digitally to determine theexact position of the sun in east-west direction Again thesystem is also given some predefined values based on the sunrsquosgeographical location in the north-south direction Overallthe entire system can intelligently track the sunrsquos movementboth in horizontal and vertical axis In order to simplifythe design and implementation process the whole system isdivided into two parts
These are as follows
(A) mechanical system design(B) electrical circuit design
(A) Mechanical System Design Assembling the mechanicalsystem was the most challenging part of this system becausethe objective was to make an energy efficient solar trackingsystemwhich demanded intelligent operations of the trackingmotors Generally one of these motors is used for dailytracking (east-west motion) and other for making a seasonaltracking (north-south motion) So the daily tracking motoroperates continuously based on light sensors and the annualmotion tracking motor operates only a few times over theyear So for design and implementation process the wholemechanical system is mainly divided into three parts asfollows
(1) linear actuator(2) panel carrier(3) panel carrier rotator
(1) Linear ActuatorA linear actuator converts circularmotionto a linear vertical motion in contrast to the circular motionof a conventional electric motorThe linear vertical motion is
used for creating the seasonal angle of the sun In this trackingsystem linear actuator consists of one stepper motor screwthread bolt bearing circular rod and some pieces of woodFigure 2 shows the mechanical design and structure of linearactuator Experimentally it is found that this mechanicalstructure has a special feature of high weight lifting using alow power stepper motor
Linear actuator gives the linear motion in vertical axis(upward and downward) and is connected to one end of panelcarrier through a straight single rod hook The rod hook isattached to the wooden frameThere are some bolts and theseare tied with seven 15-inch long circular rods of 2mm diame-ter There is also a 13-inch long screw thread and its diameteris 6mm A bolt is attached in themiddle of the wooden frameand this bolt is also tied with the screw thread Four circularrods are also mortised through the wooden frame
The wooden frame moves up and down along with thebolt and the single rod hook It works in such a way thatthe wooden frame does not let the bolt move along withthe thread screw rather when the thread screw moves thenthe four circular rods mortised into the wooden frame causethe bolt to move up or down Now when the single rodhook moves upward or downward it moves along with thepanel carrier The two ends of screw thread are placed in twobearings which helps it to rotate smoothlyThese bearings aremortised into the roof and floor One gear is also placed at thebottom of the screw thread and this gear is connected to thestepper motor gear which is placed on the floor of the linearactuator body The floor and roof of the linear actuator aremade ofwoodwhich holds all the linear actuator instruments
(2) Panel CarrierPanel carrier is basically a rectangular framemade of aluminum which holds the solar panel with the helpof a circular rod One end of the horizontal base of the panelcarrier is attached with the single rod hook of linear actuatorand other with the panel carrier rotator Figure 3 shows thedesign and implementation of panel carrier A stepper motor
4 Journal of Renewable Energy
(a) (b)
Figure 3 Design and implementation of panel carrier (a) implementation and placement of panel carrier with the linear actuator and panelcarrier rotator (b) hardware design of Panel carrier in computer aided drafting tool
(a) (b)
Figure 4 Design and implementation of panel carrier rotator (a) implementation and placement of panel carrier rotator with the panelcarrier and a wooden base (b) hardware design of panel carrier rotator in computer aided drafting tool
with a gear is placed on the body of the aluminium frameWhen the stepper motor rotates along with its gear then thepanel rotates from east to west by tracking sunrsquos daily motionactively
The light sensors are placed at the two ends of solar panelAgain the rectangular aluminium frame has a rectangularmortise in its horizontal base Single circular rod hook fromlinear actuator goes through this mortise Thus it helps to liftthe panel carrier in a semi-circular path to get sunrsquos tilt anglecaused by seasonalannual motion While the linear actuatorlifts one end of panel carrier the other end needs to be fixedwith a panel carrier rotator to get the perfect circular motion
(3) Panel Carrier Rotator Panel carrier rotator is used to holdone end of the horizontal base of the solar panel carrierOne screw thread gear and position sensors are used in thispanel carrier rotator to give a circular movement to the panelcarrier Its base is fixed on a wooden floor Figure 4 showsthe design and implementation of panel carrier rotator andFigure 5 shows the experimental setup of the hybrid dual axissolar tracker
(B) Electrical Circuit Design The whole electrical systemis mainly divided into three units These are sensor unitcontrol unit and movement adjustment unit Sensor unitsenses three different parameters (light time and position)and converts it to appropriate electrical signals Then theelectrical signals from sensor unit are sent to control unitControl unit determines the direction of themovement of themotors both in the horizontal and vertical axes Finally themovement adjustment unit adjusts the position of the solarmodule by receiving signal from the control unitThis adjust-ment is done by using two geared unipolar stepper motorsFigure 6 shows the overall block diagram of the wholesystem
(1) Sensor Unit The sensor unit consists of three sensor cir-cuits These are as follows
(a) light sensor
(b) real time clock
(c) position sensor
Journal of Renewable Energy 5
Figure 5 Experimental setup of the Hybrid dual axis solar tracker
Lightsensor
Real time clock
Position sensor
Mic
roco
ntro
ller Motor
driver
Motordriver
Stepper motor
Stepper motor
Sensor unit Control unit Movement adjustment unit
Figure 6 Block diagram of the electrical circuit
(a) Light Sensor Light sensors are used for measuring lightintensity and generating a corresponding analog voltagesignal into the input of the analog to digital converter of themicrocontroller Since this is a hybrid dual axis solar trackingsystem so to track the sunrsquos daily motion continuously thatis from east to west a pair of light dependent resistors (LDR)is used as light sensors On the other hand the sunrsquos annualmotion that is from north to south is tracked by the realtime clock (RTC) device and position sensor
A light dependent resistor (LDR) is a resistor whoseresistance decreases with increasing incident light intensityFigure 7 shows the basic LDR circuit and Table 1 shows thedifferent specifications of LDR used in the tracking system[19]The relationship between the resistance 119877LDR (resistanceof LDR) and light intensity (Lux) for a typical LDR is given infollowing equation [20]
119877LDR = (500
Lux) kΩ (1)
where 119877LDR = Resistance of LDR
(b) Real Time Clock Real time clock is a clock device thatkeeps track of the current time There are different types ofreal time clock (RTC) device among them DS1307 is usedhere This is a battery-backed real time clock (RTC) that isconnected to microcontroller via I2C bus to keep track oftime even if it is reprogrammed or if the power is lost
10
R1
RLDR
Light sensor output
Figure 7 Basic LDR circuit
battery
SCL to controller 65
73
1SDA to controller
SCLSDA
SOUTVBATDS1307
U2R1 R2
Xcrystal
3V
X1
X2
Figure 8 Real time clock circuit
This device is suitable for data logging clock-buildingtime stamping timers alarms and so forth Microcontrollertakes the month and hour values from the RTC device totrack the sunrsquos annual motion and the darkness of night totake the solar panel at its initial position Figure 8 shows thebasic RTC circuit In the figure U2 is the RTC chip Addressand data from RTC chip are transferred serially through anI2C bidirectional bus The two I2C signals are serial data(SDA) and serial clock (SCL) and these two signals are sentto controller with two pull-up resistors 119877
1and 119877
2 Together
these signalsmake it possible to support serial transmission of8 bit bytes of data-7 bit device addresses plus control bits-overthe two-wire serial bus 119883crystal is a 32768 kHz quartz crystalused for required clock generation for RTC chip And B1 is a3-volt battery used for power backup in case of power failure
(c) Position Sensor Position sensor detects the sunrsquos annualmotion A variable resistor is used here as position sensor
6 Journal of Renewable Energy
Table 1 Specification of LDR
Dark resistance(MΩ)
Illuminated resistance(kΩ)
Sensitivity(Ωlux)
Spectral application range(nm)
Rise time(ms)
Fall time(ms)
20 5ndash20 09 400ndash700 70 15
R1
RVRPosition sensor output 50
Figure 9 Position sensor circuit
Figure 9 shows a variable resistor connected to anotherresistor119877
1 So when the resistivity of variable resistor changes
the position sensor output also changesThe output from thiscircuit goes to controller and different voltages in the outputof position sensor circuit represent different latitude angle ofthe sun for its annual motion
Position sensor is placed in the panel carrier rotatorWhen linear actuator moves linearly then panel carrierrotator rotates a semicircular path which causes the positionsensor to change its voltage level The panel carrier rotatorrotates 50∘ degree in a semicircular path with respect tothe horizontal axis as in the experimental location sunrsquoslatitude angle changes in between this 50∘ The panel carrierrotator can rotate 75∘ in both sides which may also beapplicable in other locations In that case the sensor has tobe calibrated accurately For 12 months different 12 valuesof sunrsquos latitude angle are predetermined and set in themicrocontroller and with respect to these values microcon-troller decides how much to move the linear actuator Panelcarrier rotator rotates due to the linear actuatorrsquos linearlyupward and downward motion with the panel carrier Agear is placed with the panel carrier rotator which alsorotates with it This gear rotation causes the variable resistorrsquosgear to rotate and this is how the resistivity of the variableresistor changesThus the signal is changing from the positionsensor
(2) Control Unit Microcontroller is the main control unit ofthis whole system The output from the sensor unit comes to
the input of the microcontroller which determines the direc-tion of themovement of themotors both in the horizontal andvertical axes For this research ATmega32 microcontroller isused This is from the Atmel AVR family Figure 10 showsthe main flowchart of the microcontroller programmingFigure 11 shows another flowchart of the microcontrollerprogramming which is a part of the main flowchart showedin Figure 10
(3) Movement Adjustment Unit Movement adjustment unitconsists of two geared unipolar stepper motors along withtheir motor driver deviceThe output frommicrocontroller issent to the motor driver which executes the proper sequenceto turn the stepper motors in the required direction To runthe unipolar stepper motor in full drive or half drive modeULN2803 is used as motor driver IC This driver is an arrayof eight Darlington transistors Darlington pair is a singletransistor with a high current gain Thus the current gainis required for motor drive and it reduces the circuit spaceand complexity Figure 12 shows the unipolar stepper motormotor driver device and Darlington pair
The two full geared stepper motors are used here for theaccurate tracking of the sun For our experimental purposea small scale system was implemented for 3-watt solar panelThe specifications of solar panel and gear and stepper motorsare listed as follows
Specifications of solar panel as load of the motor
mass of solar panel119898 = 075Kg
Journal of Renewable Energy 7
Start
While time is 700 am
Take reading from ADC port and RTC
If the time is 2200 pm
Break
While sunlight is bright
Take reading from ADC port and RTC
If light brightness is same or low or dark
Stop the panel motor
Break
If sunlight in east side is bright
If sunlight in west side is bright
Run the panel motor in clock wise
direction
Run the panel motor in anticlockwise direction
While there is no light
Take reading from ADC port and RTC
Take the panel motor towards east direction
If time is 2100 pm
Break
Take reading from ADC port and RTC
While there is
1
2
low light
Take reading from ADC port and
RTC
Stop the motor
If it is dark or time is 2000 pm
Break
While time is 300 am
Take reading from ADC port
and RTC
If time is 700 am
Break
Figure 10 Main flowchart of microcontroller programming
length of solar panel 119871 = 0165mwidth of solar panel119863 = 023mheight of solar panel119867 = 0015m
volume of solar panel V = 119871times119863times119867 = 569times10minus4m3density 120588 = (119898V) = 131810 kgsdotmminus3
Specifications of gears
number of gear teeth1198731 = 1198732 = 24
mass of gear1198981198661= 1198981198662= 5 times 10
minus3 kgdiameter of gear119863
1198661= 1198631198662= 0027m
Specifications of motor
inertia of motor 119869119898asymp 0
pull-out torque = 0147Nsdotmpull-out frequency 119891 = 100Hzfriction coefficient 120583 = 005
step angle 120579119904= 0044
∘angle coefficient 119899 = 36∘120579
119904= 8181
For the pull-out frequency of 100Hz the required motortorque to rotate the panel is calculated as follows [21ndash23]
Calculation of moment of inertia is given as followsInertia of the load is
119869119871=
120587
32
times 120588 times 119871 times 1198634
times (
1198732
1198731
)
2
= 00597 kg sdotm2 (2)
inertia of gear 1 is
1198691198661=
1
8
times 1198981198661times 1198631198661
2
times (
1198732
1198731
)
2
(3)
inertia of gear 2 is
1198691198662=
1
8
times 1198981198662times 1198631198662
2
(4)
number of gear teeth1198731 = 1198732 so
1198691198661= 1198691198662=
1
8
times 1198981198662times 1198631198662
2
= 456 times 10minus7 kg sdotm2 (5)
8 Journal of Renewable Energy
If position sensor angle
1
= sun altitude angle
Stop the linear actuator motor
While month is from January to June
sun altitude angle sun altitude angle
Run the linear actuator motor in clockwise
Run the linear actuator motor in anti-clockwise
Take reading from ADC port and RTC
sun altitude angle
Stop the liner actuator motor and break
While month is from July to December
Take reading from ADC port and RTC
sun altitude angle
Stop the linear actuator motor and break
Run the linear actuator motor in
clockwise
Run the linear actuator motor in
anticlockwise
2
If position sensor angle =If position sensor angle =
If position sensor angle ge If position sensor angle le
Figure 11 Continuation of main flowchart of microcontroller programming
So inertia of the system is
119869119879= 119869119871+ 1198691198661+ 1198691198662+ 119869119898= 00597 kg sdotm2 (6)
Calculation of acceleration torque is given as followsNow acceleration torque is
119879119886= 119869119879times
120587 times 120579119904
180 times 119899
times 1198912
= 560 times 10minus3N sdotm (7)
Force to rotate the load is
119865 = 119898 times 119892 (sin 120579 + 120583 times cos 120579) = 03675N sdotm (8)
Calculation of load torque is given as followsNow load torque is
119879119871=
119865 times 119863
2
+ 119879119865= 00423N sdotm (9)
here load torque due to friction 119879119865asymp 0
Calculation of required motor torque is given as followsTotal calculated torque is
119879119879= 119879119886+ 119879119871= 00479N sdotm (10)
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
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Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
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Solar EnergyJournal of
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Wind EnergyJournal of
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Nuclear EnergyInternational Journal of
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High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
2 Journal of Renewable Energy
Sun
West
NorthEarthrsquos surface
South
East
120573
120572
Figure 1 Illustration of the solar angles (a) altitude angle 120572 (b)azimuthal angle 120573 The solar path corresponds to a day in the earlyfall or late winter seasons in the northern hemisphere that is justprior to the spring equinox or just after the fall equinox Solar noonis the time of day when 120573 = 180 degree that is the sun is directly atsouth and is halfway between sunrise and sunset
advanced scientific discoveries the introductions of auto-mated systems improve existing power generation by 50 [8]
There are mainly two types of solar trackers on the basisof their movement degrees of freedoms These are single axissolar tracker and dual axis solar tracker Again these twosystems are further classified on the basis of their trackingtechnologies Active passive and chronological trackers arethree of them [9 10]
Previous researchers used single axis tracking systemwhich follows only the sunrsquos daily motion [11] But the earthfollows a complex motion that consists of the daily motionand the annual motion The daily motion causes the sun toappear in the east to west direction over the earth whereasthe annual motion causes the sun to tilt at a particular anglewhile moving along east to west direction [12]
Figure 1 shows the daily and annual motion of the sunThe sunrsquos location in the sky relative to a location on thesurface of the earth can be specified by two angles as shownin Figure 1They are (1) the solar altitude angle (120572) and (2) thesolar azimuth angle (120573) Angle120572 is the angle between the sunrsquosposition and the horizontal plane of the earthrsquos surface whileangle120573 specifies the angle between a vertical plane containingthe solar disk and a line running due south [13]
Solar tracking is best achieved when the tilt angle ofthe solar tracking systems is synchronized with the seasonalchanges of the sunrsquos altitude An ideal tracker would allowthe solar modules to point towards the sun compensatingfor both changes in the altitude angle of the sun (throughoutthe day) and latitudinal offset of the sun (during seasonalchanges) So the maximum efficiency of the solar panel is notbeing used by single axis tracking systemwhereas double axistracking would ensure a cosine effectiveness of one
In active tracking or continuous tracking the position ofthe sun in the sky during the day is continuously determinedby sensors The sensors will trigger the motor or actuatorto move the mounting system so that the solar panels willalways face the sun throughout the day If the sunlight is notperpendicular to the tracker then there will be a differencein light intensity on one light sensor compared to anotherThis difference can be used to determine in which direction
the tracker has to be tilted in order to be perpendicularto the sun This method of sun tracking is reasonablyaccurate except on very cloudy days when it is hard forthe sensors to determine the position of the sun in the sky[14]
Passive tracker unlike an active tracker which determinesthe position of the sun in the sky moves in response to animbalance in pressure between two points at both ends ofthe tracker The imbalance is caused by solar heat creatinggas pressure on a ldquolow boiling point compressed gas fluidthat is driven to one side or the otherrdquo which then movesthe structure However this method of sun tracking is notaccurate [15 16]
A chronological tracker is a time-based tracking systemwhere the structure is moved at a fixed rate throughout theday as well for different months Thus the motor or actuatoris controlled to rotate at a slow average rate of one revolutionper day (15∘ per hour) This method of sun tracking is moreenergy efficient [17]
To track the sunrsquos movement accurately dual axis trackingsystem is necessary The activecontinuous tracking systemtracks the sun for light intensity variation with precisionHence the power gain from this system is very high [18]But to achieve this power gain the system uses two differentmotors continuously for two different axes As a result italways consumes a certain amount of extra power comparedto time-based tracking system Therefore to reduce thispower loss a combination of active and time-based trackingcould be the suitable alternative to this system Finally themotivation of the research was to design and implement ahybrid dual axis solar tracking system which reduces themotor power consumption while tracking accurately
A simple energy efficient and rugged tracking modelis presented in this paper in order to build a hybrid dualaxis solar tracker To track the sunrsquos daily motion thatis from east to west direction a pair of light sensors areused and to track the seasonal motion of the sun real timeclock (RTC) is used to create the accurate azimuth anglefrom some predetermined parameters The light intensity iscompared by microcontroller and it generates the suitablecontrol signals to move the motors in proper direction Soa driver circuit is used to increase the voltage and currentlevel for the operation of the motors Two full geared steppermotors are used for rotating the solar module in two differentaxes
A versatile mechanical system is introduced as a linearactuator to create proper tilt angle In addition this linearactuator has high weight lifting capability which is observedexperimentally It is found that energy efficient hybrid dualaxis tracking yields almost same energy as continuous dualaxis solar tracking system It is also observed that in hybridtracking system one motor can remain idle for one monthand thus reduces more than 44 of power consumption ascompared with continuous dual axis solar tracking systemThismechanismproved significant benefit of reducing energyconsumption by hybrid tracker sacrificing a very little track-ing loss This paper also represents the comparative studybetween the continuousactive and hybrid solar trackingsystem
Journal of Renewable Energy 3
(a) (b)
Figure 2 Design and implementation of linear actuator (a) implementation and placement of linear actuator with the aluminium body ofpanel carrier (b) hardware design of linear actuator in computer aided drafting tool
2 Design and Implementation Process
The whole work involves the reading of different sensorvalues and then comparing them digitally to determine theexact position of the sun in east-west direction Again thesystem is also given some predefined values based on the sunrsquosgeographical location in the north-south direction Overallthe entire system can intelligently track the sunrsquos movementboth in horizontal and vertical axis In order to simplifythe design and implementation process the whole system isdivided into two parts
These are as follows
(A) mechanical system design(B) electrical circuit design
(A) Mechanical System Design Assembling the mechanicalsystem was the most challenging part of this system becausethe objective was to make an energy efficient solar trackingsystemwhich demanded intelligent operations of the trackingmotors Generally one of these motors is used for dailytracking (east-west motion) and other for making a seasonaltracking (north-south motion) So the daily tracking motoroperates continuously based on light sensors and the annualmotion tracking motor operates only a few times over theyear So for design and implementation process the wholemechanical system is mainly divided into three parts asfollows
(1) linear actuator(2) panel carrier(3) panel carrier rotator
(1) Linear ActuatorA linear actuator converts circularmotionto a linear vertical motion in contrast to the circular motionof a conventional electric motorThe linear vertical motion is
used for creating the seasonal angle of the sun In this trackingsystem linear actuator consists of one stepper motor screwthread bolt bearing circular rod and some pieces of woodFigure 2 shows the mechanical design and structure of linearactuator Experimentally it is found that this mechanicalstructure has a special feature of high weight lifting using alow power stepper motor
Linear actuator gives the linear motion in vertical axis(upward and downward) and is connected to one end of panelcarrier through a straight single rod hook The rod hook isattached to the wooden frameThere are some bolts and theseare tied with seven 15-inch long circular rods of 2mm diame-ter There is also a 13-inch long screw thread and its diameteris 6mm A bolt is attached in themiddle of the wooden frameand this bolt is also tied with the screw thread Four circularrods are also mortised through the wooden frame
The wooden frame moves up and down along with thebolt and the single rod hook It works in such a way thatthe wooden frame does not let the bolt move along withthe thread screw rather when the thread screw moves thenthe four circular rods mortised into the wooden frame causethe bolt to move up or down Now when the single rodhook moves upward or downward it moves along with thepanel carrier The two ends of screw thread are placed in twobearings which helps it to rotate smoothlyThese bearings aremortised into the roof and floor One gear is also placed at thebottom of the screw thread and this gear is connected to thestepper motor gear which is placed on the floor of the linearactuator body The floor and roof of the linear actuator aremade ofwoodwhich holds all the linear actuator instruments
(2) Panel CarrierPanel carrier is basically a rectangular framemade of aluminum which holds the solar panel with the helpof a circular rod One end of the horizontal base of the panelcarrier is attached with the single rod hook of linear actuatorand other with the panel carrier rotator Figure 3 shows thedesign and implementation of panel carrier A stepper motor
4 Journal of Renewable Energy
(a) (b)
Figure 3 Design and implementation of panel carrier (a) implementation and placement of panel carrier with the linear actuator and panelcarrier rotator (b) hardware design of Panel carrier in computer aided drafting tool
(a) (b)
Figure 4 Design and implementation of panel carrier rotator (a) implementation and placement of panel carrier rotator with the panelcarrier and a wooden base (b) hardware design of panel carrier rotator in computer aided drafting tool
with a gear is placed on the body of the aluminium frameWhen the stepper motor rotates along with its gear then thepanel rotates from east to west by tracking sunrsquos daily motionactively
The light sensors are placed at the two ends of solar panelAgain the rectangular aluminium frame has a rectangularmortise in its horizontal base Single circular rod hook fromlinear actuator goes through this mortise Thus it helps to liftthe panel carrier in a semi-circular path to get sunrsquos tilt anglecaused by seasonalannual motion While the linear actuatorlifts one end of panel carrier the other end needs to be fixedwith a panel carrier rotator to get the perfect circular motion
(3) Panel Carrier Rotator Panel carrier rotator is used to holdone end of the horizontal base of the solar panel carrierOne screw thread gear and position sensors are used in thispanel carrier rotator to give a circular movement to the panelcarrier Its base is fixed on a wooden floor Figure 4 showsthe design and implementation of panel carrier rotator andFigure 5 shows the experimental setup of the hybrid dual axissolar tracker
(B) Electrical Circuit Design The whole electrical systemis mainly divided into three units These are sensor unitcontrol unit and movement adjustment unit Sensor unitsenses three different parameters (light time and position)and converts it to appropriate electrical signals Then theelectrical signals from sensor unit are sent to control unitControl unit determines the direction of themovement of themotors both in the horizontal and vertical axes Finally themovement adjustment unit adjusts the position of the solarmodule by receiving signal from the control unitThis adjust-ment is done by using two geared unipolar stepper motorsFigure 6 shows the overall block diagram of the wholesystem
(1) Sensor Unit The sensor unit consists of three sensor cir-cuits These are as follows
(a) light sensor
(b) real time clock
(c) position sensor
Journal of Renewable Energy 5
Figure 5 Experimental setup of the Hybrid dual axis solar tracker
Lightsensor
Real time clock
Position sensor
Mic
roco
ntro
ller Motor
driver
Motordriver
Stepper motor
Stepper motor
Sensor unit Control unit Movement adjustment unit
Figure 6 Block diagram of the electrical circuit
(a) Light Sensor Light sensors are used for measuring lightintensity and generating a corresponding analog voltagesignal into the input of the analog to digital converter of themicrocontroller Since this is a hybrid dual axis solar trackingsystem so to track the sunrsquos daily motion continuously thatis from east to west a pair of light dependent resistors (LDR)is used as light sensors On the other hand the sunrsquos annualmotion that is from north to south is tracked by the realtime clock (RTC) device and position sensor
A light dependent resistor (LDR) is a resistor whoseresistance decreases with increasing incident light intensityFigure 7 shows the basic LDR circuit and Table 1 shows thedifferent specifications of LDR used in the tracking system[19]The relationship between the resistance 119877LDR (resistanceof LDR) and light intensity (Lux) for a typical LDR is given infollowing equation [20]
119877LDR = (500
Lux) kΩ (1)
where 119877LDR = Resistance of LDR
(b) Real Time Clock Real time clock is a clock device thatkeeps track of the current time There are different types ofreal time clock (RTC) device among them DS1307 is usedhere This is a battery-backed real time clock (RTC) that isconnected to microcontroller via I2C bus to keep track oftime even if it is reprogrammed or if the power is lost
10
R1
RLDR
Light sensor output
Figure 7 Basic LDR circuit
battery
SCL to controller 65
73
1SDA to controller
SCLSDA
SOUTVBATDS1307
U2R1 R2
Xcrystal
3V
X1
X2
Figure 8 Real time clock circuit
This device is suitable for data logging clock-buildingtime stamping timers alarms and so forth Microcontrollertakes the month and hour values from the RTC device totrack the sunrsquos annual motion and the darkness of night totake the solar panel at its initial position Figure 8 shows thebasic RTC circuit In the figure U2 is the RTC chip Addressand data from RTC chip are transferred serially through anI2C bidirectional bus The two I2C signals are serial data(SDA) and serial clock (SCL) and these two signals are sentto controller with two pull-up resistors 119877
1and 119877
2 Together
these signalsmake it possible to support serial transmission of8 bit bytes of data-7 bit device addresses plus control bits-overthe two-wire serial bus 119883crystal is a 32768 kHz quartz crystalused for required clock generation for RTC chip And B1 is a3-volt battery used for power backup in case of power failure
(c) Position Sensor Position sensor detects the sunrsquos annualmotion A variable resistor is used here as position sensor
6 Journal of Renewable Energy
Table 1 Specification of LDR
Dark resistance(MΩ)
Illuminated resistance(kΩ)
Sensitivity(Ωlux)
Spectral application range(nm)
Rise time(ms)
Fall time(ms)
20 5ndash20 09 400ndash700 70 15
R1
RVRPosition sensor output 50
Figure 9 Position sensor circuit
Figure 9 shows a variable resistor connected to anotherresistor119877
1 So when the resistivity of variable resistor changes
the position sensor output also changesThe output from thiscircuit goes to controller and different voltages in the outputof position sensor circuit represent different latitude angle ofthe sun for its annual motion
Position sensor is placed in the panel carrier rotatorWhen linear actuator moves linearly then panel carrierrotator rotates a semicircular path which causes the positionsensor to change its voltage level The panel carrier rotatorrotates 50∘ degree in a semicircular path with respect tothe horizontal axis as in the experimental location sunrsquoslatitude angle changes in between this 50∘ The panel carrierrotator can rotate 75∘ in both sides which may also beapplicable in other locations In that case the sensor has tobe calibrated accurately For 12 months different 12 valuesof sunrsquos latitude angle are predetermined and set in themicrocontroller and with respect to these values microcon-troller decides how much to move the linear actuator Panelcarrier rotator rotates due to the linear actuatorrsquos linearlyupward and downward motion with the panel carrier Agear is placed with the panel carrier rotator which alsorotates with it This gear rotation causes the variable resistorrsquosgear to rotate and this is how the resistivity of the variableresistor changesThus the signal is changing from the positionsensor
(2) Control Unit Microcontroller is the main control unit ofthis whole system The output from the sensor unit comes to
the input of the microcontroller which determines the direc-tion of themovement of themotors both in the horizontal andvertical axes For this research ATmega32 microcontroller isused This is from the Atmel AVR family Figure 10 showsthe main flowchart of the microcontroller programmingFigure 11 shows another flowchart of the microcontrollerprogramming which is a part of the main flowchart showedin Figure 10
(3) Movement Adjustment Unit Movement adjustment unitconsists of two geared unipolar stepper motors along withtheir motor driver deviceThe output frommicrocontroller issent to the motor driver which executes the proper sequenceto turn the stepper motors in the required direction To runthe unipolar stepper motor in full drive or half drive modeULN2803 is used as motor driver IC This driver is an arrayof eight Darlington transistors Darlington pair is a singletransistor with a high current gain Thus the current gainis required for motor drive and it reduces the circuit spaceand complexity Figure 12 shows the unipolar stepper motormotor driver device and Darlington pair
The two full geared stepper motors are used here for theaccurate tracking of the sun For our experimental purposea small scale system was implemented for 3-watt solar panelThe specifications of solar panel and gear and stepper motorsare listed as follows
Specifications of solar panel as load of the motor
mass of solar panel119898 = 075Kg
Journal of Renewable Energy 7
Start
While time is 700 am
Take reading from ADC port and RTC
If the time is 2200 pm
Break
While sunlight is bright
Take reading from ADC port and RTC
If light brightness is same or low or dark
Stop the panel motor
Break
If sunlight in east side is bright
If sunlight in west side is bright
Run the panel motor in clock wise
direction
Run the panel motor in anticlockwise direction
While there is no light
Take reading from ADC port and RTC
Take the panel motor towards east direction
If time is 2100 pm
Break
Take reading from ADC port and RTC
While there is
1
2
low light
Take reading from ADC port and
RTC
Stop the motor
If it is dark or time is 2000 pm
Break
While time is 300 am
Take reading from ADC port
and RTC
If time is 700 am
Break
Figure 10 Main flowchart of microcontroller programming
length of solar panel 119871 = 0165mwidth of solar panel119863 = 023mheight of solar panel119867 = 0015m
volume of solar panel V = 119871times119863times119867 = 569times10minus4m3density 120588 = (119898V) = 131810 kgsdotmminus3
Specifications of gears
number of gear teeth1198731 = 1198732 = 24
mass of gear1198981198661= 1198981198662= 5 times 10
minus3 kgdiameter of gear119863
1198661= 1198631198662= 0027m
Specifications of motor
inertia of motor 119869119898asymp 0
pull-out torque = 0147Nsdotmpull-out frequency 119891 = 100Hzfriction coefficient 120583 = 005
step angle 120579119904= 0044
∘angle coefficient 119899 = 36∘120579
119904= 8181
For the pull-out frequency of 100Hz the required motortorque to rotate the panel is calculated as follows [21ndash23]
Calculation of moment of inertia is given as followsInertia of the load is
119869119871=
120587
32
times 120588 times 119871 times 1198634
times (
1198732
1198731
)
2
= 00597 kg sdotm2 (2)
inertia of gear 1 is
1198691198661=
1
8
times 1198981198661times 1198631198661
2
times (
1198732
1198731
)
2
(3)
inertia of gear 2 is
1198691198662=
1
8
times 1198981198662times 1198631198662
2
(4)
number of gear teeth1198731 = 1198732 so
1198691198661= 1198691198662=
1
8
times 1198981198662times 1198631198662
2
= 456 times 10minus7 kg sdotm2 (5)
8 Journal of Renewable Energy
If position sensor angle
1
= sun altitude angle
Stop the linear actuator motor
While month is from January to June
sun altitude angle sun altitude angle
Run the linear actuator motor in clockwise
Run the linear actuator motor in anti-clockwise
Take reading from ADC port and RTC
sun altitude angle
Stop the liner actuator motor and break
While month is from July to December
Take reading from ADC port and RTC
sun altitude angle
Stop the linear actuator motor and break
Run the linear actuator motor in
clockwise
Run the linear actuator motor in
anticlockwise
2
If position sensor angle =If position sensor angle =
If position sensor angle ge If position sensor angle le
Figure 11 Continuation of main flowchart of microcontroller programming
So inertia of the system is
119869119879= 119869119871+ 1198691198661+ 1198691198662+ 119869119898= 00597 kg sdotm2 (6)
Calculation of acceleration torque is given as followsNow acceleration torque is
119879119886= 119869119879times
120587 times 120579119904
180 times 119899
times 1198912
= 560 times 10minus3N sdotm (7)
Force to rotate the load is
119865 = 119898 times 119892 (sin 120579 + 120583 times cos 120579) = 03675N sdotm (8)
Calculation of load torque is given as followsNow load torque is
119879119871=
119865 times 119863
2
+ 119879119865= 00423N sdotm (9)
here load torque due to friction 119879119865asymp 0
Calculation of required motor torque is given as followsTotal calculated torque is
119879119879= 119879119886+ 119879119871= 00479N sdotm (10)
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
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Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
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Solar EnergyJournal of
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Wind EnergyJournal of
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Nuclear EnergyInternational Journal of
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High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Renewable Energy 3
(a) (b)
Figure 2 Design and implementation of linear actuator (a) implementation and placement of linear actuator with the aluminium body ofpanel carrier (b) hardware design of linear actuator in computer aided drafting tool
2 Design and Implementation Process
The whole work involves the reading of different sensorvalues and then comparing them digitally to determine theexact position of the sun in east-west direction Again thesystem is also given some predefined values based on the sunrsquosgeographical location in the north-south direction Overallthe entire system can intelligently track the sunrsquos movementboth in horizontal and vertical axis In order to simplifythe design and implementation process the whole system isdivided into two parts
These are as follows
(A) mechanical system design(B) electrical circuit design
(A) Mechanical System Design Assembling the mechanicalsystem was the most challenging part of this system becausethe objective was to make an energy efficient solar trackingsystemwhich demanded intelligent operations of the trackingmotors Generally one of these motors is used for dailytracking (east-west motion) and other for making a seasonaltracking (north-south motion) So the daily tracking motoroperates continuously based on light sensors and the annualmotion tracking motor operates only a few times over theyear So for design and implementation process the wholemechanical system is mainly divided into three parts asfollows
(1) linear actuator(2) panel carrier(3) panel carrier rotator
(1) Linear ActuatorA linear actuator converts circularmotionto a linear vertical motion in contrast to the circular motionof a conventional electric motorThe linear vertical motion is
used for creating the seasonal angle of the sun In this trackingsystem linear actuator consists of one stepper motor screwthread bolt bearing circular rod and some pieces of woodFigure 2 shows the mechanical design and structure of linearactuator Experimentally it is found that this mechanicalstructure has a special feature of high weight lifting using alow power stepper motor
Linear actuator gives the linear motion in vertical axis(upward and downward) and is connected to one end of panelcarrier through a straight single rod hook The rod hook isattached to the wooden frameThere are some bolts and theseare tied with seven 15-inch long circular rods of 2mm diame-ter There is also a 13-inch long screw thread and its diameteris 6mm A bolt is attached in themiddle of the wooden frameand this bolt is also tied with the screw thread Four circularrods are also mortised through the wooden frame
The wooden frame moves up and down along with thebolt and the single rod hook It works in such a way thatthe wooden frame does not let the bolt move along withthe thread screw rather when the thread screw moves thenthe four circular rods mortised into the wooden frame causethe bolt to move up or down Now when the single rodhook moves upward or downward it moves along with thepanel carrier The two ends of screw thread are placed in twobearings which helps it to rotate smoothlyThese bearings aremortised into the roof and floor One gear is also placed at thebottom of the screw thread and this gear is connected to thestepper motor gear which is placed on the floor of the linearactuator body The floor and roof of the linear actuator aremade ofwoodwhich holds all the linear actuator instruments
(2) Panel CarrierPanel carrier is basically a rectangular framemade of aluminum which holds the solar panel with the helpof a circular rod One end of the horizontal base of the panelcarrier is attached with the single rod hook of linear actuatorand other with the panel carrier rotator Figure 3 shows thedesign and implementation of panel carrier A stepper motor
4 Journal of Renewable Energy
(a) (b)
Figure 3 Design and implementation of panel carrier (a) implementation and placement of panel carrier with the linear actuator and panelcarrier rotator (b) hardware design of Panel carrier in computer aided drafting tool
(a) (b)
Figure 4 Design and implementation of panel carrier rotator (a) implementation and placement of panel carrier rotator with the panelcarrier and a wooden base (b) hardware design of panel carrier rotator in computer aided drafting tool
with a gear is placed on the body of the aluminium frameWhen the stepper motor rotates along with its gear then thepanel rotates from east to west by tracking sunrsquos daily motionactively
The light sensors are placed at the two ends of solar panelAgain the rectangular aluminium frame has a rectangularmortise in its horizontal base Single circular rod hook fromlinear actuator goes through this mortise Thus it helps to liftthe panel carrier in a semi-circular path to get sunrsquos tilt anglecaused by seasonalannual motion While the linear actuatorlifts one end of panel carrier the other end needs to be fixedwith a panel carrier rotator to get the perfect circular motion
(3) Panel Carrier Rotator Panel carrier rotator is used to holdone end of the horizontal base of the solar panel carrierOne screw thread gear and position sensors are used in thispanel carrier rotator to give a circular movement to the panelcarrier Its base is fixed on a wooden floor Figure 4 showsthe design and implementation of panel carrier rotator andFigure 5 shows the experimental setup of the hybrid dual axissolar tracker
(B) Electrical Circuit Design The whole electrical systemis mainly divided into three units These are sensor unitcontrol unit and movement adjustment unit Sensor unitsenses three different parameters (light time and position)and converts it to appropriate electrical signals Then theelectrical signals from sensor unit are sent to control unitControl unit determines the direction of themovement of themotors both in the horizontal and vertical axes Finally themovement adjustment unit adjusts the position of the solarmodule by receiving signal from the control unitThis adjust-ment is done by using two geared unipolar stepper motorsFigure 6 shows the overall block diagram of the wholesystem
(1) Sensor Unit The sensor unit consists of three sensor cir-cuits These are as follows
(a) light sensor
(b) real time clock
(c) position sensor
Journal of Renewable Energy 5
Figure 5 Experimental setup of the Hybrid dual axis solar tracker
Lightsensor
Real time clock
Position sensor
Mic
roco
ntro
ller Motor
driver
Motordriver
Stepper motor
Stepper motor
Sensor unit Control unit Movement adjustment unit
Figure 6 Block diagram of the electrical circuit
(a) Light Sensor Light sensors are used for measuring lightintensity and generating a corresponding analog voltagesignal into the input of the analog to digital converter of themicrocontroller Since this is a hybrid dual axis solar trackingsystem so to track the sunrsquos daily motion continuously thatis from east to west a pair of light dependent resistors (LDR)is used as light sensors On the other hand the sunrsquos annualmotion that is from north to south is tracked by the realtime clock (RTC) device and position sensor
A light dependent resistor (LDR) is a resistor whoseresistance decreases with increasing incident light intensityFigure 7 shows the basic LDR circuit and Table 1 shows thedifferent specifications of LDR used in the tracking system[19]The relationship between the resistance 119877LDR (resistanceof LDR) and light intensity (Lux) for a typical LDR is given infollowing equation [20]
119877LDR = (500
Lux) kΩ (1)
where 119877LDR = Resistance of LDR
(b) Real Time Clock Real time clock is a clock device thatkeeps track of the current time There are different types ofreal time clock (RTC) device among them DS1307 is usedhere This is a battery-backed real time clock (RTC) that isconnected to microcontroller via I2C bus to keep track oftime even if it is reprogrammed or if the power is lost
10
R1
RLDR
Light sensor output
Figure 7 Basic LDR circuit
battery
SCL to controller 65
73
1SDA to controller
SCLSDA
SOUTVBATDS1307
U2R1 R2
Xcrystal
3V
X1
X2
Figure 8 Real time clock circuit
This device is suitable for data logging clock-buildingtime stamping timers alarms and so forth Microcontrollertakes the month and hour values from the RTC device totrack the sunrsquos annual motion and the darkness of night totake the solar panel at its initial position Figure 8 shows thebasic RTC circuit In the figure U2 is the RTC chip Addressand data from RTC chip are transferred serially through anI2C bidirectional bus The two I2C signals are serial data(SDA) and serial clock (SCL) and these two signals are sentto controller with two pull-up resistors 119877
1and 119877
2 Together
these signalsmake it possible to support serial transmission of8 bit bytes of data-7 bit device addresses plus control bits-overthe two-wire serial bus 119883crystal is a 32768 kHz quartz crystalused for required clock generation for RTC chip And B1 is a3-volt battery used for power backup in case of power failure
(c) Position Sensor Position sensor detects the sunrsquos annualmotion A variable resistor is used here as position sensor
6 Journal of Renewable Energy
Table 1 Specification of LDR
Dark resistance(MΩ)
Illuminated resistance(kΩ)
Sensitivity(Ωlux)
Spectral application range(nm)
Rise time(ms)
Fall time(ms)
20 5ndash20 09 400ndash700 70 15
R1
RVRPosition sensor output 50
Figure 9 Position sensor circuit
Figure 9 shows a variable resistor connected to anotherresistor119877
1 So when the resistivity of variable resistor changes
the position sensor output also changesThe output from thiscircuit goes to controller and different voltages in the outputof position sensor circuit represent different latitude angle ofthe sun for its annual motion
Position sensor is placed in the panel carrier rotatorWhen linear actuator moves linearly then panel carrierrotator rotates a semicircular path which causes the positionsensor to change its voltage level The panel carrier rotatorrotates 50∘ degree in a semicircular path with respect tothe horizontal axis as in the experimental location sunrsquoslatitude angle changes in between this 50∘ The panel carrierrotator can rotate 75∘ in both sides which may also beapplicable in other locations In that case the sensor has tobe calibrated accurately For 12 months different 12 valuesof sunrsquos latitude angle are predetermined and set in themicrocontroller and with respect to these values microcon-troller decides how much to move the linear actuator Panelcarrier rotator rotates due to the linear actuatorrsquos linearlyupward and downward motion with the panel carrier Agear is placed with the panel carrier rotator which alsorotates with it This gear rotation causes the variable resistorrsquosgear to rotate and this is how the resistivity of the variableresistor changesThus the signal is changing from the positionsensor
(2) Control Unit Microcontroller is the main control unit ofthis whole system The output from the sensor unit comes to
the input of the microcontroller which determines the direc-tion of themovement of themotors both in the horizontal andvertical axes For this research ATmega32 microcontroller isused This is from the Atmel AVR family Figure 10 showsthe main flowchart of the microcontroller programmingFigure 11 shows another flowchart of the microcontrollerprogramming which is a part of the main flowchart showedin Figure 10
(3) Movement Adjustment Unit Movement adjustment unitconsists of two geared unipolar stepper motors along withtheir motor driver deviceThe output frommicrocontroller issent to the motor driver which executes the proper sequenceto turn the stepper motors in the required direction To runthe unipolar stepper motor in full drive or half drive modeULN2803 is used as motor driver IC This driver is an arrayof eight Darlington transistors Darlington pair is a singletransistor with a high current gain Thus the current gainis required for motor drive and it reduces the circuit spaceand complexity Figure 12 shows the unipolar stepper motormotor driver device and Darlington pair
The two full geared stepper motors are used here for theaccurate tracking of the sun For our experimental purposea small scale system was implemented for 3-watt solar panelThe specifications of solar panel and gear and stepper motorsare listed as follows
Specifications of solar panel as load of the motor
mass of solar panel119898 = 075Kg
Journal of Renewable Energy 7
Start
While time is 700 am
Take reading from ADC port and RTC
If the time is 2200 pm
Break
While sunlight is bright
Take reading from ADC port and RTC
If light brightness is same or low or dark
Stop the panel motor
Break
If sunlight in east side is bright
If sunlight in west side is bright
Run the panel motor in clock wise
direction
Run the panel motor in anticlockwise direction
While there is no light
Take reading from ADC port and RTC
Take the panel motor towards east direction
If time is 2100 pm
Break
Take reading from ADC port and RTC
While there is
1
2
low light
Take reading from ADC port and
RTC
Stop the motor
If it is dark or time is 2000 pm
Break
While time is 300 am
Take reading from ADC port
and RTC
If time is 700 am
Break
Figure 10 Main flowchart of microcontroller programming
length of solar panel 119871 = 0165mwidth of solar panel119863 = 023mheight of solar panel119867 = 0015m
volume of solar panel V = 119871times119863times119867 = 569times10minus4m3density 120588 = (119898V) = 131810 kgsdotmminus3
Specifications of gears
number of gear teeth1198731 = 1198732 = 24
mass of gear1198981198661= 1198981198662= 5 times 10
minus3 kgdiameter of gear119863
1198661= 1198631198662= 0027m
Specifications of motor
inertia of motor 119869119898asymp 0
pull-out torque = 0147Nsdotmpull-out frequency 119891 = 100Hzfriction coefficient 120583 = 005
step angle 120579119904= 0044
∘angle coefficient 119899 = 36∘120579
119904= 8181
For the pull-out frequency of 100Hz the required motortorque to rotate the panel is calculated as follows [21ndash23]
Calculation of moment of inertia is given as followsInertia of the load is
119869119871=
120587
32
times 120588 times 119871 times 1198634
times (
1198732
1198731
)
2
= 00597 kg sdotm2 (2)
inertia of gear 1 is
1198691198661=
1
8
times 1198981198661times 1198631198661
2
times (
1198732
1198731
)
2
(3)
inertia of gear 2 is
1198691198662=
1
8
times 1198981198662times 1198631198662
2
(4)
number of gear teeth1198731 = 1198732 so
1198691198661= 1198691198662=
1
8
times 1198981198662times 1198631198662
2
= 456 times 10minus7 kg sdotm2 (5)
8 Journal of Renewable Energy
If position sensor angle
1
= sun altitude angle
Stop the linear actuator motor
While month is from January to June
sun altitude angle sun altitude angle
Run the linear actuator motor in clockwise
Run the linear actuator motor in anti-clockwise
Take reading from ADC port and RTC
sun altitude angle
Stop the liner actuator motor and break
While month is from July to December
Take reading from ADC port and RTC
sun altitude angle
Stop the linear actuator motor and break
Run the linear actuator motor in
clockwise
Run the linear actuator motor in
anticlockwise
2
If position sensor angle =If position sensor angle =
If position sensor angle ge If position sensor angle le
Figure 11 Continuation of main flowchart of microcontroller programming
So inertia of the system is
119869119879= 119869119871+ 1198691198661+ 1198691198662+ 119869119898= 00597 kg sdotm2 (6)
Calculation of acceleration torque is given as followsNow acceleration torque is
119879119886= 119869119879times
120587 times 120579119904
180 times 119899
times 1198912
= 560 times 10minus3N sdotm (7)
Force to rotate the load is
119865 = 119898 times 119892 (sin 120579 + 120583 times cos 120579) = 03675N sdotm (8)
Calculation of load torque is given as followsNow load torque is
119879119871=
119865 times 119863
2
+ 119879119865= 00423N sdotm (9)
here load torque due to friction 119879119865asymp 0
Calculation of required motor torque is given as followsTotal calculated torque is
119879119879= 119879119886+ 119879119871= 00479N sdotm (10)
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
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Solar EnergyJournal of
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Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
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High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
4 Journal of Renewable Energy
(a) (b)
Figure 3 Design and implementation of panel carrier (a) implementation and placement of panel carrier with the linear actuator and panelcarrier rotator (b) hardware design of Panel carrier in computer aided drafting tool
(a) (b)
Figure 4 Design and implementation of panel carrier rotator (a) implementation and placement of panel carrier rotator with the panelcarrier and a wooden base (b) hardware design of panel carrier rotator in computer aided drafting tool
with a gear is placed on the body of the aluminium frameWhen the stepper motor rotates along with its gear then thepanel rotates from east to west by tracking sunrsquos daily motionactively
The light sensors are placed at the two ends of solar panelAgain the rectangular aluminium frame has a rectangularmortise in its horizontal base Single circular rod hook fromlinear actuator goes through this mortise Thus it helps to liftthe panel carrier in a semi-circular path to get sunrsquos tilt anglecaused by seasonalannual motion While the linear actuatorlifts one end of panel carrier the other end needs to be fixedwith a panel carrier rotator to get the perfect circular motion
(3) Panel Carrier Rotator Panel carrier rotator is used to holdone end of the horizontal base of the solar panel carrierOne screw thread gear and position sensors are used in thispanel carrier rotator to give a circular movement to the panelcarrier Its base is fixed on a wooden floor Figure 4 showsthe design and implementation of panel carrier rotator andFigure 5 shows the experimental setup of the hybrid dual axissolar tracker
(B) Electrical Circuit Design The whole electrical systemis mainly divided into three units These are sensor unitcontrol unit and movement adjustment unit Sensor unitsenses three different parameters (light time and position)and converts it to appropriate electrical signals Then theelectrical signals from sensor unit are sent to control unitControl unit determines the direction of themovement of themotors both in the horizontal and vertical axes Finally themovement adjustment unit adjusts the position of the solarmodule by receiving signal from the control unitThis adjust-ment is done by using two geared unipolar stepper motorsFigure 6 shows the overall block diagram of the wholesystem
(1) Sensor Unit The sensor unit consists of three sensor cir-cuits These are as follows
(a) light sensor
(b) real time clock
(c) position sensor
Journal of Renewable Energy 5
Figure 5 Experimental setup of the Hybrid dual axis solar tracker
Lightsensor
Real time clock
Position sensor
Mic
roco
ntro
ller Motor
driver
Motordriver
Stepper motor
Stepper motor
Sensor unit Control unit Movement adjustment unit
Figure 6 Block diagram of the electrical circuit
(a) Light Sensor Light sensors are used for measuring lightintensity and generating a corresponding analog voltagesignal into the input of the analog to digital converter of themicrocontroller Since this is a hybrid dual axis solar trackingsystem so to track the sunrsquos daily motion continuously thatis from east to west a pair of light dependent resistors (LDR)is used as light sensors On the other hand the sunrsquos annualmotion that is from north to south is tracked by the realtime clock (RTC) device and position sensor
A light dependent resistor (LDR) is a resistor whoseresistance decreases with increasing incident light intensityFigure 7 shows the basic LDR circuit and Table 1 shows thedifferent specifications of LDR used in the tracking system[19]The relationship between the resistance 119877LDR (resistanceof LDR) and light intensity (Lux) for a typical LDR is given infollowing equation [20]
119877LDR = (500
Lux) kΩ (1)
where 119877LDR = Resistance of LDR
(b) Real Time Clock Real time clock is a clock device thatkeeps track of the current time There are different types ofreal time clock (RTC) device among them DS1307 is usedhere This is a battery-backed real time clock (RTC) that isconnected to microcontroller via I2C bus to keep track oftime even if it is reprogrammed or if the power is lost
10
R1
RLDR
Light sensor output
Figure 7 Basic LDR circuit
battery
SCL to controller 65
73
1SDA to controller
SCLSDA
SOUTVBATDS1307
U2R1 R2
Xcrystal
3V
X1
X2
Figure 8 Real time clock circuit
This device is suitable for data logging clock-buildingtime stamping timers alarms and so forth Microcontrollertakes the month and hour values from the RTC device totrack the sunrsquos annual motion and the darkness of night totake the solar panel at its initial position Figure 8 shows thebasic RTC circuit In the figure U2 is the RTC chip Addressand data from RTC chip are transferred serially through anI2C bidirectional bus The two I2C signals are serial data(SDA) and serial clock (SCL) and these two signals are sentto controller with two pull-up resistors 119877
1and 119877
2 Together
these signalsmake it possible to support serial transmission of8 bit bytes of data-7 bit device addresses plus control bits-overthe two-wire serial bus 119883crystal is a 32768 kHz quartz crystalused for required clock generation for RTC chip And B1 is a3-volt battery used for power backup in case of power failure
(c) Position Sensor Position sensor detects the sunrsquos annualmotion A variable resistor is used here as position sensor
6 Journal of Renewable Energy
Table 1 Specification of LDR
Dark resistance(MΩ)
Illuminated resistance(kΩ)
Sensitivity(Ωlux)
Spectral application range(nm)
Rise time(ms)
Fall time(ms)
20 5ndash20 09 400ndash700 70 15
R1
RVRPosition sensor output 50
Figure 9 Position sensor circuit
Figure 9 shows a variable resistor connected to anotherresistor119877
1 So when the resistivity of variable resistor changes
the position sensor output also changesThe output from thiscircuit goes to controller and different voltages in the outputof position sensor circuit represent different latitude angle ofthe sun for its annual motion
Position sensor is placed in the panel carrier rotatorWhen linear actuator moves linearly then panel carrierrotator rotates a semicircular path which causes the positionsensor to change its voltage level The panel carrier rotatorrotates 50∘ degree in a semicircular path with respect tothe horizontal axis as in the experimental location sunrsquoslatitude angle changes in between this 50∘ The panel carrierrotator can rotate 75∘ in both sides which may also beapplicable in other locations In that case the sensor has tobe calibrated accurately For 12 months different 12 valuesof sunrsquos latitude angle are predetermined and set in themicrocontroller and with respect to these values microcon-troller decides how much to move the linear actuator Panelcarrier rotator rotates due to the linear actuatorrsquos linearlyupward and downward motion with the panel carrier Agear is placed with the panel carrier rotator which alsorotates with it This gear rotation causes the variable resistorrsquosgear to rotate and this is how the resistivity of the variableresistor changesThus the signal is changing from the positionsensor
(2) Control Unit Microcontroller is the main control unit ofthis whole system The output from the sensor unit comes to
the input of the microcontroller which determines the direc-tion of themovement of themotors both in the horizontal andvertical axes For this research ATmega32 microcontroller isused This is from the Atmel AVR family Figure 10 showsthe main flowchart of the microcontroller programmingFigure 11 shows another flowchart of the microcontrollerprogramming which is a part of the main flowchart showedin Figure 10
(3) Movement Adjustment Unit Movement adjustment unitconsists of two geared unipolar stepper motors along withtheir motor driver deviceThe output frommicrocontroller issent to the motor driver which executes the proper sequenceto turn the stepper motors in the required direction To runthe unipolar stepper motor in full drive or half drive modeULN2803 is used as motor driver IC This driver is an arrayof eight Darlington transistors Darlington pair is a singletransistor with a high current gain Thus the current gainis required for motor drive and it reduces the circuit spaceand complexity Figure 12 shows the unipolar stepper motormotor driver device and Darlington pair
The two full geared stepper motors are used here for theaccurate tracking of the sun For our experimental purposea small scale system was implemented for 3-watt solar panelThe specifications of solar panel and gear and stepper motorsare listed as follows
Specifications of solar panel as load of the motor
mass of solar panel119898 = 075Kg
Journal of Renewable Energy 7
Start
While time is 700 am
Take reading from ADC port and RTC
If the time is 2200 pm
Break
While sunlight is bright
Take reading from ADC port and RTC
If light brightness is same or low or dark
Stop the panel motor
Break
If sunlight in east side is bright
If sunlight in west side is bright
Run the panel motor in clock wise
direction
Run the panel motor in anticlockwise direction
While there is no light
Take reading from ADC port and RTC
Take the panel motor towards east direction
If time is 2100 pm
Break
Take reading from ADC port and RTC
While there is
1
2
low light
Take reading from ADC port and
RTC
Stop the motor
If it is dark or time is 2000 pm
Break
While time is 300 am
Take reading from ADC port
and RTC
If time is 700 am
Break
Figure 10 Main flowchart of microcontroller programming
length of solar panel 119871 = 0165mwidth of solar panel119863 = 023mheight of solar panel119867 = 0015m
volume of solar panel V = 119871times119863times119867 = 569times10minus4m3density 120588 = (119898V) = 131810 kgsdotmminus3
Specifications of gears
number of gear teeth1198731 = 1198732 = 24
mass of gear1198981198661= 1198981198662= 5 times 10
minus3 kgdiameter of gear119863
1198661= 1198631198662= 0027m
Specifications of motor
inertia of motor 119869119898asymp 0
pull-out torque = 0147Nsdotmpull-out frequency 119891 = 100Hzfriction coefficient 120583 = 005
step angle 120579119904= 0044
∘angle coefficient 119899 = 36∘120579
119904= 8181
For the pull-out frequency of 100Hz the required motortorque to rotate the panel is calculated as follows [21ndash23]
Calculation of moment of inertia is given as followsInertia of the load is
119869119871=
120587
32
times 120588 times 119871 times 1198634
times (
1198732
1198731
)
2
= 00597 kg sdotm2 (2)
inertia of gear 1 is
1198691198661=
1
8
times 1198981198661times 1198631198661
2
times (
1198732
1198731
)
2
(3)
inertia of gear 2 is
1198691198662=
1
8
times 1198981198662times 1198631198662
2
(4)
number of gear teeth1198731 = 1198732 so
1198691198661= 1198691198662=
1
8
times 1198981198662times 1198631198662
2
= 456 times 10minus7 kg sdotm2 (5)
8 Journal of Renewable Energy
If position sensor angle
1
= sun altitude angle
Stop the linear actuator motor
While month is from January to June
sun altitude angle sun altitude angle
Run the linear actuator motor in clockwise
Run the linear actuator motor in anti-clockwise
Take reading from ADC port and RTC
sun altitude angle
Stop the liner actuator motor and break
While month is from July to December
Take reading from ADC port and RTC
sun altitude angle
Stop the linear actuator motor and break
Run the linear actuator motor in
clockwise
Run the linear actuator motor in
anticlockwise
2
If position sensor angle =If position sensor angle =
If position sensor angle ge If position sensor angle le
Figure 11 Continuation of main flowchart of microcontroller programming
So inertia of the system is
119869119879= 119869119871+ 1198691198661+ 1198691198662+ 119869119898= 00597 kg sdotm2 (6)
Calculation of acceleration torque is given as followsNow acceleration torque is
119879119886= 119869119879times
120587 times 120579119904
180 times 119899
times 1198912
= 560 times 10minus3N sdotm (7)
Force to rotate the load is
119865 = 119898 times 119892 (sin 120579 + 120583 times cos 120579) = 03675N sdotm (8)
Calculation of load torque is given as followsNow load torque is
119879119871=
119865 times 119863
2
+ 119879119865= 00423N sdotm (9)
here load torque due to friction 119879119865asymp 0
Calculation of required motor torque is given as followsTotal calculated torque is
119879119879= 119879119886+ 119879119871= 00479N sdotm (10)
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Renewable Energy 5
Figure 5 Experimental setup of the Hybrid dual axis solar tracker
Lightsensor
Real time clock
Position sensor
Mic
roco
ntro
ller Motor
driver
Motordriver
Stepper motor
Stepper motor
Sensor unit Control unit Movement adjustment unit
Figure 6 Block diagram of the electrical circuit
(a) Light Sensor Light sensors are used for measuring lightintensity and generating a corresponding analog voltagesignal into the input of the analog to digital converter of themicrocontroller Since this is a hybrid dual axis solar trackingsystem so to track the sunrsquos daily motion continuously thatis from east to west a pair of light dependent resistors (LDR)is used as light sensors On the other hand the sunrsquos annualmotion that is from north to south is tracked by the realtime clock (RTC) device and position sensor
A light dependent resistor (LDR) is a resistor whoseresistance decreases with increasing incident light intensityFigure 7 shows the basic LDR circuit and Table 1 shows thedifferent specifications of LDR used in the tracking system[19]The relationship between the resistance 119877LDR (resistanceof LDR) and light intensity (Lux) for a typical LDR is given infollowing equation [20]
119877LDR = (500
Lux) kΩ (1)
where 119877LDR = Resistance of LDR
(b) Real Time Clock Real time clock is a clock device thatkeeps track of the current time There are different types ofreal time clock (RTC) device among them DS1307 is usedhere This is a battery-backed real time clock (RTC) that isconnected to microcontroller via I2C bus to keep track oftime even if it is reprogrammed or if the power is lost
10
R1
RLDR
Light sensor output
Figure 7 Basic LDR circuit
battery
SCL to controller 65
73
1SDA to controller
SCLSDA
SOUTVBATDS1307
U2R1 R2
Xcrystal
3V
X1
X2
Figure 8 Real time clock circuit
This device is suitable for data logging clock-buildingtime stamping timers alarms and so forth Microcontrollertakes the month and hour values from the RTC device totrack the sunrsquos annual motion and the darkness of night totake the solar panel at its initial position Figure 8 shows thebasic RTC circuit In the figure U2 is the RTC chip Addressand data from RTC chip are transferred serially through anI2C bidirectional bus The two I2C signals are serial data(SDA) and serial clock (SCL) and these two signals are sentto controller with two pull-up resistors 119877
1and 119877
2 Together
these signalsmake it possible to support serial transmission of8 bit bytes of data-7 bit device addresses plus control bits-overthe two-wire serial bus 119883crystal is a 32768 kHz quartz crystalused for required clock generation for RTC chip And B1 is a3-volt battery used for power backup in case of power failure
(c) Position Sensor Position sensor detects the sunrsquos annualmotion A variable resistor is used here as position sensor
6 Journal of Renewable Energy
Table 1 Specification of LDR
Dark resistance(MΩ)
Illuminated resistance(kΩ)
Sensitivity(Ωlux)
Spectral application range(nm)
Rise time(ms)
Fall time(ms)
20 5ndash20 09 400ndash700 70 15
R1
RVRPosition sensor output 50
Figure 9 Position sensor circuit
Figure 9 shows a variable resistor connected to anotherresistor119877
1 So when the resistivity of variable resistor changes
the position sensor output also changesThe output from thiscircuit goes to controller and different voltages in the outputof position sensor circuit represent different latitude angle ofthe sun for its annual motion
Position sensor is placed in the panel carrier rotatorWhen linear actuator moves linearly then panel carrierrotator rotates a semicircular path which causes the positionsensor to change its voltage level The panel carrier rotatorrotates 50∘ degree in a semicircular path with respect tothe horizontal axis as in the experimental location sunrsquoslatitude angle changes in between this 50∘ The panel carrierrotator can rotate 75∘ in both sides which may also beapplicable in other locations In that case the sensor has tobe calibrated accurately For 12 months different 12 valuesof sunrsquos latitude angle are predetermined and set in themicrocontroller and with respect to these values microcon-troller decides how much to move the linear actuator Panelcarrier rotator rotates due to the linear actuatorrsquos linearlyupward and downward motion with the panel carrier Agear is placed with the panel carrier rotator which alsorotates with it This gear rotation causes the variable resistorrsquosgear to rotate and this is how the resistivity of the variableresistor changesThus the signal is changing from the positionsensor
(2) Control Unit Microcontroller is the main control unit ofthis whole system The output from the sensor unit comes to
the input of the microcontroller which determines the direc-tion of themovement of themotors both in the horizontal andvertical axes For this research ATmega32 microcontroller isused This is from the Atmel AVR family Figure 10 showsthe main flowchart of the microcontroller programmingFigure 11 shows another flowchart of the microcontrollerprogramming which is a part of the main flowchart showedin Figure 10
(3) Movement Adjustment Unit Movement adjustment unitconsists of two geared unipolar stepper motors along withtheir motor driver deviceThe output frommicrocontroller issent to the motor driver which executes the proper sequenceto turn the stepper motors in the required direction To runthe unipolar stepper motor in full drive or half drive modeULN2803 is used as motor driver IC This driver is an arrayof eight Darlington transistors Darlington pair is a singletransistor with a high current gain Thus the current gainis required for motor drive and it reduces the circuit spaceand complexity Figure 12 shows the unipolar stepper motormotor driver device and Darlington pair
The two full geared stepper motors are used here for theaccurate tracking of the sun For our experimental purposea small scale system was implemented for 3-watt solar panelThe specifications of solar panel and gear and stepper motorsare listed as follows
Specifications of solar panel as load of the motor
mass of solar panel119898 = 075Kg
Journal of Renewable Energy 7
Start
While time is 700 am
Take reading from ADC port and RTC
If the time is 2200 pm
Break
While sunlight is bright
Take reading from ADC port and RTC
If light brightness is same or low or dark
Stop the panel motor
Break
If sunlight in east side is bright
If sunlight in west side is bright
Run the panel motor in clock wise
direction
Run the panel motor in anticlockwise direction
While there is no light
Take reading from ADC port and RTC
Take the panel motor towards east direction
If time is 2100 pm
Break
Take reading from ADC port and RTC
While there is
1
2
low light
Take reading from ADC port and
RTC
Stop the motor
If it is dark or time is 2000 pm
Break
While time is 300 am
Take reading from ADC port
and RTC
If time is 700 am
Break
Figure 10 Main flowchart of microcontroller programming
length of solar panel 119871 = 0165mwidth of solar panel119863 = 023mheight of solar panel119867 = 0015m
volume of solar panel V = 119871times119863times119867 = 569times10minus4m3density 120588 = (119898V) = 131810 kgsdotmminus3
Specifications of gears
number of gear teeth1198731 = 1198732 = 24
mass of gear1198981198661= 1198981198662= 5 times 10
minus3 kgdiameter of gear119863
1198661= 1198631198662= 0027m
Specifications of motor
inertia of motor 119869119898asymp 0
pull-out torque = 0147Nsdotmpull-out frequency 119891 = 100Hzfriction coefficient 120583 = 005
step angle 120579119904= 0044
∘angle coefficient 119899 = 36∘120579
119904= 8181
For the pull-out frequency of 100Hz the required motortorque to rotate the panel is calculated as follows [21ndash23]
Calculation of moment of inertia is given as followsInertia of the load is
119869119871=
120587
32
times 120588 times 119871 times 1198634
times (
1198732
1198731
)
2
= 00597 kg sdotm2 (2)
inertia of gear 1 is
1198691198661=
1
8
times 1198981198661times 1198631198661
2
times (
1198732
1198731
)
2
(3)
inertia of gear 2 is
1198691198662=
1
8
times 1198981198662times 1198631198662
2
(4)
number of gear teeth1198731 = 1198732 so
1198691198661= 1198691198662=
1
8
times 1198981198662times 1198631198662
2
= 456 times 10minus7 kg sdotm2 (5)
8 Journal of Renewable Energy
If position sensor angle
1
= sun altitude angle
Stop the linear actuator motor
While month is from January to June
sun altitude angle sun altitude angle
Run the linear actuator motor in clockwise
Run the linear actuator motor in anti-clockwise
Take reading from ADC port and RTC
sun altitude angle
Stop the liner actuator motor and break
While month is from July to December
Take reading from ADC port and RTC
sun altitude angle
Stop the linear actuator motor and break
Run the linear actuator motor in
clockwise
Run the linear actuator motor in
anticlockwise
2
If position sensor angle =If position sensor angle =
If position sensor angle ge If position sensor angle le
Figure 11 Continuation of main flowchart of microcontroller programming
So inertia of the system is
119869119879= 119869119871+ 1198691198661+ 1198691198662+ 119869119898= 00597 kg sdotm2 (6)
Calculation of acceleration torque is given as followsNow acceleration torque is
119879119886= 119869119879times
120587 times 120579119904
180 times 119899
times 1198912
= 560 times 10minus3N sdotm (7)
Force to rotate the load is
119865 = 119898 times 119892 (sin 120579 + 120583 times cos 120579) = 03675N sdotm (8)
Calculation of load torque is given as followsNow load torque is
119879119871=
119865 times 119863
2
+ 119879119865= 00423N sdotm (9)
here load torque due to friction 119879119865asymp 0
Calculation of required motor torque is given as followsTotal calculated torque is
119879119879= 119879119886+ 119879119871= 00479N sdotm (10)
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
6 Journal of Renewable Energy
Table 1 Specification of LDR
Dark resistance(MΩ)
Illuminated resistance(kΩ)
Sensitivity(Ωlux)
Spectral application range(nm)
Rise time(ms)
Fall time(ms)
20 5ndash20 09 400ndash700 70 15
R1
RVRPosition sensor output 50
Figure 9 Position sensor circuit
Figure 9 shows a variable resistor connected to anotherresistor119877
1 So when the resistivity of variable resistor changes
the position sensor output also changesThe output from thiscircuit goes to controller and different voltages in the outputof position sensor circuit represent different latitude angle ofthe sun for its annual motion
Position sensor is placed in the panel carrier rotatorWhen linear actuator moves linearly then panel carrierrotator rotates a semicircular path which causes the positionsensor to change its voltage level The panel carrier rotatorrotates 50∘ degree in a semicircular path with respect tothe horizontal axis as in the experimental location sunrsquoslatitude angle changes in between this 50∘ The panel carrierrotator can rotate 75∘ in both sides which may also beapplicable in other locations In that case the sensor has tobe calibrated accurately For 12 months different 12 valuesof sunrsquos latitude angle are predetermined and set in themicrocontroller and with respect to these values microcon-troller decides how much to move the linear actuator Panelcarrier rotator rotates due to the linear actuatorrsquos linearlyupward and downward motion with the panel carrier Agear is placed with the panel carrier rotator which alsorotates with it This gear rotation causes the variable resistorrsquosgear to rotate and this is how the resistivity of the variableresistor changesThus the signal is changing from the positionsensor
(2) Control Unit Microcontroller is the main control unit ofthis whole system The output from the sensor unit comes to
the input of the microcontroller which determines the direc-tion of themovement of themotors both in the horizontal andvertical axes For this research ATmega32 microcontroller isused This is from the Atmel AVR family Figure 10 showsthe main flowchart of the microcontroller programmingFigure 11 shows another flowchart of the microcontrollerprogramming which is a part of the main flowchart showedin Figure 10
(3) Movement Adjustment Unit Movement adjustment unitconsists of two geared unipolar stepper motors along withtheir motor driver deviceThe output frommicrocontroller issent to the motor driver which executes the proper sequenceto turn the stepper motors in the required direction To runthe unipolar stepper motor in full drive or half drive modeULN2803 is used as motor driver IC This driver is an arrayof eight Darlington transistors Darlington pair is a singletransistor with a high current gain Thus the current gainis required for motor drive and it reduces the circuit spaceand complexity Figure 12 shows the unipolar stepper motormotor driver device and Darlington pair
The two full geared stepper motors are used here for theaccurate tracking of the sun For our experimental purposea small scale system was implemented for 3-watt solar panelThe specifications of solar panel and gear and stepper motorsare listed as follows
Specifications of solar panel as load of the motor
mass of solar panel119898 = 075Kg
Journal of Renewable Energy 7
Start
While time is 700 am
Take reading from ADC port and RTC
If the time is 2200 pm
Break
While sunlight is bright
Take reading from ADC port and RTC
If light brightness is same or low or dark
Stop the panel motor
Break
If sunlight in east side is bright
If sunlight in west side is bright
Run the panel motor in clock wise
direction
Run the panel motor in anticlockwise direction
While there is no light
Take reading from ADC port and RTC
Take the panel motor towards east direction
If time is 2100 pm
Break
Take reading from ADC port and RTC
While there is
1
2
low light
Take reading from ADC port and
RTC
Stop the motor
If it is dark or time is 2000 pm
Break
While time is 300 am
Take reading from ADC port
and RTC
If time is 700 am
Break
Figure 10 Main flowchart of microcontroller programming
length of solar panel 119871 = 0165mwidth of solar panel119863 = 023mheight of solar panel119867 = 0015m
volume of solar panel V = 119871times119863times119867 = 569times10minus4m3density 120588 = (119898V) = 131810 kgsdotmminus3
Specifications of gears
number of gear teeth1198731 = 1198732 = 24
mass of gear1198981198661= 1198981198662= 5 times 10
minus3 kgdiameter of gear119863
1198661= 1198631198662= 0027m
Specifications of motor
inertia of motor 119869119898asymp 0
pull-out torque = 0147Nsdotmpull-out frequency 119891 = 100Hzfriction coefficient 120583 = 005
step angle 120579119904= 0044
∘angle coefficient 119899 = 36∘120579
119904= 8181
For the pull-out frequency of 100Hz the required motortorque to rotate the panel is calculated as follows [21ndash23]
Calculation of moment of inertia is given as followsInertia of the load is
119869119871=
120587
32
times 120588 times 119871 times 1198634
times (
1198732
1198731
)
2
= 00597 kg sdotm2 (2)
inertia of gear 1 is
1198691198661=
1
8
times 1198981198661times 1198631198661
2
times (
1198732
1198731
)
2
(3)
inertia of gear 2 is
1198691198662=
1
8
times 1198981198662times 1198631198662
2
(4)
number of gear teeth1198731 = 1198732 so
1198691198661= 1198691198662=
1
8
times 1198981198662times 1198631198662
2
= 456 times 10minus7 kg sdotm2 (5)
8 Journal of Renewable Energy
If position sensor angle
1
= sun altitude angle
Stop the linear actuator motor
While month is from January to June
sun altitude angle sun altitude angle
Run the linear actuator motor in clockwise
Run the linear actuator motor in anti-clockwise
Take reading from ADC port and RTC
sun altitude angle
Stop the liner actuator motor and break
While month is from July to December
Take reading from ADC port and RTC
sun altitude angle
Stop the linear actuator motor and break
Run the linear actuator motor in
clockwise
Run the linear actuator motor in
anticlockwise
2
If position sensor angle =If position sensor angle =
If position sensor angle ge If position sensor angle le
Figure 11 Continuation of main flowchart of microcontroller programming
So inertia of the system is
119869119879= 119869119871+ 1198691198661+ 1198691198662+ 119869119898= 00597 kg sdotm2 (6)
Calculation of acceleration torque is given as followsNow acceleration torque is
119879119886= 119869119879times
120587 times 120579119904
180 times 119899
times 1198912
= 560 times 10minus3N sdotm (7)
Force to rotate the load is
119865 = 119898 times 119892 (sin 120579 + 120583 times cos 120579) = 03675N sdotm (8)
Calculation of load torque is given as followsNow load torque is
119879119871=
119865 times 119863
2
+ 119879119865= 00423N sdotm (9)
here load torque due to friction 119879119865asymp 0
Calculation of required motor torque is given as followsTotal calculated torque is
119879119879= 119879119886+ 119879119871= 00479N sdotm (10)
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Renewable Energy 7
Start
While time is 700 am
Take reading from ADC port and RTC
If the time is 2200 pm
Break
While sunlight is bright
Take reading from ADC port and RTC
If light brightness is same or low or dark
Stop the panel motor
Break
If sunlight in east side is bright
If sunlight in west side is bright
Run the panel motor in clock wise
direction
Run the panel motor in anticlockwise direction
While there is no light
Take reading from ADC port and RTC
Take the panel motor towards east direction
If time is 2100 pm
Break
Take reading from ADC port and RTC
While there is
1
2
low light
Take reading from ADC port and
RTC
Stop the motor
If it is dark or time is 2000 pm
Break
While time is 300 am
Take reading from ADC port
and RTC
If time is 700 am
Break
Figure 10 Main flowchart of microcontroller programming
length of solar panel 119871 = 0165mwidth of solar panel119863 = 023mheight of solar panel119867 = 0015m
volume of solar panel V = 119871times119863times119867 = 569times10minus4m3density 120588 = (119898V) = 131810 kgsdotmminus3
Specifications of gears
number of gear teeth1198731 = 1198732 = 24
mass of gear1198981198661= 1198981198662= 5 times 10
minus3 kgdiameter of gear119863
1198661= 1198631198662= 0027m
Specifications of motor
inertia of motor 119869119898asymp 0
pull-out torque = 0147Nsdotmpull-out frequency 119891 = 100Hzfriction coefficient 120583 = 005
step angle 120579119904= 0044
∘angle coefficient 119899 = 36∘120579
119904= 8181
For the pull-out frequency of 100Hz the required motortorque to rotate the panel is calculated as follows [21ndash23]
Calculation of moment of inertia is given as followsInertia of the load is
119869119871=
120587
32
times 120588 times 119871 times 1198634
times (
1198732
1198731
)
2
= 00597 kg sdotm2 (2)
inertia of gear 1 is
1198691198661=
1
8
times 1198981198661times 1198631198661
2
times (
1198732
1198731
)
2
(3)
inertia of gear 2 is
1198691198662=
1
8
times 1198981198662times 1198631198662
2
(4)
number of gear teeth1198731 = 1198732 so
1198691198661= 1198691198662=
1
8
times 1198981198662times 1198631198662
2
= 456 times 10minus7 kg sdotm2 (5)
8 Journal of Renewable Energy
If position sensor angle
1
= sun altitude angle
Stop the linear actuator motor
While month is from January to June
sun altitude angle sun altitude angle
Run the linear actuator motor in clockwise
Run the linear actuator motor in anti-clockwise
Take reading from ADC port and RTC
sun altitude angle
Stop the liner actuator motor and break
While month is from July to December
Take reading from ADC port and RTC
sun altitude angle
Stop the linear actuator motor and break
Run the linear actuator motor in
clockwise
Run the linear actuator motor in
anticlockwise
2
If position sensor angle =If position sensor angle =
If position sensor angle ge If position sensor angle le
Figure 11 Continuation of main flowchart of microcontroller programming
So inertia of the system is
119869119879= 119869119871+ 1198691198661+ 1198691198662+ 119869119898= 00597 kg sdotm2 (6)
Calculation of acceleration torque is given as followsNow acceleration torque is
119879119886= 119869119879times
120587 times 120579119904
180 times 119899
times 1198912
= 560 times 10minus3N sdotm (7)
Force to rotate the load is
119865 = 119898 times 119892 (sin 120579 + 120583 times cos 120579) = 03675N sdotm (8)
Calculation of load torque is given as followsNow load torque is
119879119871=
119865 times 119863
2
+ 119879119865= 00423N sdotm (9)
here load torque due to friction 119879119865asymp 0
Calculation of required motor torque is given as followsTotal calculated torque is
119879119879= 119879119886+ 119879119871= 00479N sdotm (10)
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
8 Journal of Renewable Energy
If position sensor angle
1
= sun altitude angle
Stop the linear actuator motor
While month is from January to June
sun altitude angle sun altitude angle
Run the linear actuator motor in clockwise
Run the linear actuator motor in anti-clockwise
Take reading from ADC port and RTC
sun altitude angle
Stop the liner actuator motor and break
While month is from July to December
Take reading from ADC port and RTC
sun altitude angle
Stop the linear actuator motor and break
Run the linear actuator motor in
clockwise
Run the linear actuator motor in
anticlockwise
2
If position sensor angle =If position sensor angle =
If position sensor angle ge If position sensor angle le
Figure 11 Continuation of main flowchart of microcontroller programming
So inertia of the system is
119869119879= 119869119871+ 1198691198661+ 1198691198662+ 119869119898= 00597 kg sdotm2 (6)
Calculation of acceleration torque is given as followsNow acceleration torque is
119879119886= 119869119879times
120587 times 120579119904
180 times 119899
times 1198912
= 560 times 10minus3N sdotm (7)
Force to rotate the load is
119865 = 119898 times 119892 (sin 120579 + 120583 times cos 120579) = 03675N sdotm (8)
Calculation of load torque is given as followsNow load torque is
119879119871=
119865 times 119863
2
+ 119879119865= 00423N sdotm (9)
here load torque due to friction 119879119865asymp 0
Calculation of required motor torque is given as followsTotal calculated torque is
119879119879= 119879119886+ 119879119871= 00479N sdotm (10)
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Renewable Energy 9
+888
(BC)
A1
A1A2A2
A4
A4
A3
A3
B1
1B2B3B4B5B6B7B8B
1ABCDEFGH
2345678
101817161514131211
1CCOM
U3
ULN2803
2C3C4C5C6C7C8C
B1
B2
B2
B4
B3
B3
B4
+888
(BC)
(a)
TR1
TR2
Collector
Emitter
Emitter
Base
Base
(b)
Figure 12 Movement adjustment unit (a) the unipolar stepper motor and motor driver device (ULN2803) and (b) Darlington pair
Required motor torque is
119879119872= 119870119904times 119879119879= 00958N sdotm (11)
Here safety factor119870119904= 2
there4 Required motor torque lt pull-out torqueSo from the above comparison it is clear that pull-out
torque of 0147Nsdotm of stepper motor is sufficient enough torotate the solar panel of 075 kg
3 Experimental Results and Data Analysis
(A) Comparative Study of Solar Panel Power Output Allthe experiments have been conducted in Dhaka Bangladesh(23∘421015840010158401015840N 90∘2210158403010158401015840E) Table 2 shows the current andvoltage values received from the static panel hybrid trackingsystem and continuous tracking system for different timesin a day From Table 2 it is seen that at 800 am there ismuch improvement in current by both the tracking systemscompared to the static panel But as time goes on thedifference in current among these three systems decreasesup to around 1100 am After that when the sun rotates moretowards west this difference increases again The highestcurrent of static panel hybrid tracking system and contin-uous tracking system is 047 amp 048 amp and 050 amprespectively at 1230 pm But in case of voltage the variation isless compared to current as the voltage has no direct relationwith the sun light intensity Figure 13 shows the comparisonof current versus time curves for the static panel hybridtracking system and continuous tracking system
Table 3 shows the power values of the static panel andboth the tracking systemsThepower gain of tracking systemsover static panel and between the two tracking systemsfor different times is also given in Table 3 The maximumpower output of the static panel hybrid tracking systemand continuous tracking system is found as 37036watt37824watt and 394watt respectively at 1230 pm Muchmore power gain is achieved in the morning and afternoonbecause both the tracking systems can accurately track the
0
01
02
03
04
05
06Cu
rren
t (A
)
Time (hour)
730
830
930
103
0
113
0
123
0
133
0
143
0
153
0
163
0
173
0
Current (static panel)Current (hybrid tracking)Current (continuous tracking)
Figure 13 Comparison curve comparison of current versus timecurve for the static panel hybrid tracking system and continuoustracking system
sun at these times while the static system cannot For all thesetechnologies power fall was very fast from 330 pm to 530 pmbecause of the low duration of day light
The total power of static panel hybrid tracking systemand the continuous tracking system throughout the day is4521 watt 5669watt and 5824watt respectively So theaverage power gain of hybrid tracking system over thestatic panel is 2562 Similarly the average power gain ofcontinuous tracking systemover the static panel is 2810 andover the hybrid tracking system is 419
(B) Comparison of Stepper Motor Power Consumption Thepower consumption by the stepper motors in both the solartracking system is not same Table 4 shows the comparison ofsteppermotors power consumption between the two trackingsystems
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
10 Journal of Renewable Energy
Table 2 Current and voltage values of static and tracking panel at different times in a day
Time(hour)
Static panel Hybrid tracking system Continuous tracking systemCurrent(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
Current(ampere)
Voltage(volt)
730 011 782 017 782 019 792800 014 782 021 782 023 792830 022 783 024 783 024 79900 027 79 034 8 035 8930 035 793 039 798 039 7981000 039 792 041 792 041 7921030 041 788 043 792 043 7921100 045 788 045 788 045 7881130 046 788 046 788 046 7881200 046 788 048 788 048 7881230 047 788 048 788 05 7881300 043 788 048 788 049 7881330 04 777 047 781 048 7811400 033 779 045 783 046 7931430 026 771 044 771 044 7831500 018 763 037 776 037 791530 014 754 031 77 031 7861600 011 752 025 773 026 7861630 009 741 019 771 02 7711700 007 739 013 765 015 7711730 004 733 008 75 01 764
Table 3 Power values of static and tracking panel and the corresponding power gain by tracking panel over static panel at different times ina day
Time(hour)
Static panel Hybridtracking panel
Continuoustracking panel
Power gain byhybrid tracking system
over static panel
Power gain bycontinuous tracking system
over static panel
Power gain bycontinuous tracking systemover hybrid tracking system
Power(watt)
Power(watt)
Power(watt)
730 08602 13294 15048 3529412 4283626 1165603800 10948 16422 18216 3333333 3989899 1165603830 17226 18792 1896 8333333 914557 9848485900 2133 272 28 2158088 2382143 0886076930 27755 31122 31122 1081871 1081871 28571431000 30888 32472 32472 4878049 4878049 01030 32308 34056 34056 5132723 5132723 01100 3546 3546 3546 0 0 01130 36248 36248 36248 0 0 01200 36248 37824 37824 4166667 4166667 01230 37036 37824 394 2083333 122449 01300 33884 37824 38612 1041667 122449 41330 3108 36707 37488 153295 1709347 20408161400 25707 35235 36478 2704129 2952739 20833331430 20046 33924 34452 4090909 418147 34075331500 13734 28712 2923 5216634 5301403 15325671530 10556 2387 24366 5577713 5667734 17721521600 08272 19325 20436 5719534 5952241 20356231630 06669 14649 1542 5447471 5675097 54364851700 05173 09945 11565 4798391 5527021 51730 02932 06 0764 5113333 6162304 1400778
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Journal of Renewable Energy 11
Table 4 Comparison of stepper motor power consumption
Hybrid tracking system Continuous tracking systemPower consumptionfor movement in east to west
Power consumptionfor movement in north to south
Power consumptionfor movement in east to west
Power consumptionfor movement in north to south
06 watt Almost zero asymp 0 06 watt 048 wattTotal = 06 watt Total = 108 watt
Power saved = 4444
So power saved by hybrid tracking system over continu-ous tracking system is 4444
(C) Data Analysis So from all these data it is seen thatthe hybrid dual axis tracking system has average powergeneration of 5669watt whereas the continuous trackingsystem has 5824watt Therefore continuous tracking systemhas only 42 average power gain over hybrid dual axistracking system On the other hand hybrid dual axis trackingsystem is saving 4444 system power consumption com-pared to continuous tracking systemThough the continuoustracking system gives a slight improvement in power gaindue to its continuous tracking it consumes much morepower compared to the hybrid dual axis tracking systemConsidering the case of 4444 power saving by hybridtracking system it can be concluded that the hybrid dual axistracking system can operate much more efficiently comparedto the continuous tracking system while sacrificing littleabout 42 tracking accuracy
4 Conclusion
The design implementation and testing of a hybrid dualaxis solar tracking system is presented in the study ThePerformance of the developed system was experimented andcompared with both the static and continuous dual axis solartracking system This work demonstrates that hybrid dualaxis solar tracking system can assure higher power generationcompared to static panel as well as less power consumptioncompared to continuous dual axis solar tracking system Theresult shows that the hybrid dual axis tracking system has2562 more average power gain over static system while ithas 42 less average power gain compared to continuoustracking system In hybrid dual axis solar tracking systemone motor runs continuously to track continuous movementof sun due to daily motion and another motor runs oncein a month to track suns seasonal motion But in othertrackers like in continuous solar tracker it needs tomove boththe motors continuously Thus the hybrid system is savingmotor power consumptionwhile the power gain compared toother technology is almost marginal So further comparativestudy about stepper motor power consumption shows thathybrid tracking system can save 4444 power compared tocontinuous tracking systemThis amount of power savingwillhave a significant effect in large systems like heliostat powerplants where a lot of trackers are required and power saved byall the systems will show a big amount of power Other thanthis the designed tracking system can also be implemented
for the solar thermal systems Finally the proposed design isachieved with low power consumption high accuracy andlow cost
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
The authors thank MD Ahasanul Kabir of American Inter-national University Bangladesh (AIUB) for his help with themechanical system implementation
References
[1] G Deb and A B Roy ldquoUse of solar tracking system forextracting solar energyrdquo International Journal of Computer andElectrical Engineering vol 4 no 1 pp 42ndash46 2012
[2] T Tudorache and L Kreindler ldquoDesign of a solar tracker systemfor PV power plantsrdquo Acta Polytechnica Hungarica vol 7 no 1pp 23ndash39 2010
[3] C-L Shen and C-T Tsai ldquoDouble-linear approximation algo-rithm to achieve maximum-power-point tracking for photo-voltaic arraysrdquo Energies vol 5 no 6 pp 1982ndash1997 2012
[4] K Liu ldquoDynamic characteristics and graphicmonitoring designof photovoltaic energy conversion systemrdquo WSEAS Transac-tions on Systems vol 10 no 8 pp 239ndash248 2011
[5] T Tudorache C D Oancea and L Kreindler ldquoPerformanceevaluation of a solar tracking PV panelrdquo UPB ScientificBulletin Series C Electrical Engineering vol 74 no 1 pp 3ndash102012
[6] H Mousazadeh A Keyhani A Javadi H Mobli K Abriniaand A Sharifi ldquoA review of principle and sun-trackingmethodsfor maximizing solar systems outputrdquo Renewable and Sustain-able Energy Reviews vol 13 no 8 pp 1800ndash1818 2009
[7] M Benghanem ldquoOptimization of tilt angle for solar panel Casestudy forMadinah Saudi ArabiardquoApplied Energy vol 88 no 4pp 1427ndash1433 2011
[8] C Praveen ldquoDesign of automatic dual-axis solar tracker usingmicrocontrollerrdquo in Proceedings of the International Conferenceon Computing and Control Engineering (ICCCE rsquo12) April 2012
[9] D F Fam S P Koh S K Tiong and K H Chong ldquoQualitativeanalysis of stochastic operations in dual axis solar tracking envi-ronmentrdquo Research Journal of Recent Sciences vol 1 no 9 pp74ndash78 2012
[10] AM Sharan andM Prateek ldquoAutomation ofminimum torque-based accurate solar tracking systems using microprocessorsrdquo
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
12 Journal of Renewable Energy
Journal of the Indian Institute of Science vol 86 no 5 pp 415ndash437 2006
[11] C Alexandru and M Comsit Virtual Prototyping of the SolarTracking Systems Department of Product Design and RoboticsUniversity Transilvania of Brasov Brasov Romania
[12] A Hsing Solar Panel Tracker Senior Project Electrical Engi-neering Department California Polytechnic State UniversitySan Luis Obispo Calif USA 2010
[13] N A Kelly and T L Gibson ldquoIncreasing the solar photovoltaicenergy capture on sunny and cloudy daysrdquo Solar Energy vol 85no 1 pp 111ndash125 2011
[14] M B Omar Low Cost Solar Tracker Faculty of Electrical ampElectronics Engineering Universiti Malaysia Pahang 2009
[15] A Argeseanu E Ritchie and K Leban ldquoNew low cost structurefor dual axis mount solar tracking system using adaptive solarsensorrdquo in Proceedings of the 12th International Conference onOptimization of Electrical and Electronic Equipment (OPTIMrsquo10) pp 1109ndash1114 Brasov Romania May 2010
[16] M J Clifford and D Eastwood ldquoDesign of a novel passive solartrackerrdquo Solar Energy vol 77 no 3 pp 269ndash280 2004
[17] N Barsoum ldquoFabrication of dual-axis solar tracking controllerprojectrdquo Intelligent Control and Automation vol 2 no 2 pp57ndash68 2011
[18] S Rahman R A Ferdaus M Abdul Mannan and M AMohammed ldquoDesign amp implementation of a dual axis solartracking systemrdquoAmericanAcademicamp Scholarly Research Jour-nal vol 5 no 1 pp 47ndash54 2013
[19] CdS Photoconductive Photocells Advanced Photonix httpwwwcooking-hackscomskinfrontenddefaultcookingpdfLDR-Datasheetpdf
[20] ldquoMeasure Light Intensity using Light Dependent Resistor(LDR)rdquo httpwwwemantcom316002page
[21] Motor torque calculation Leadshine technology httpwwwleadshinecomPdfCalculationpdf
[22] ldquoSelecting a steppingmotor Orientalmotorrdquo httpwwworien-tal-motorcoukmediafiles17112005105315pdf
[23] Technical reference Oriental motor httpwwworientalmotorcomproductspdfs2012-2013Gusa tech calculationpdf
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
TribologyAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
FuelsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal ofPetroleum Engineering
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Industrial EngineeringJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Power ElectronicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
CombustionJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Renewable Energy
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
StructuresJournal of
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear InstallationsScience and Technology of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Solar EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Wind EnergyJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Nuclear EnergyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
High Energy PhysicsAdvances in
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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